酸性溶液中におけるZnSの湿式酸化に関する電気化学的研究

抄録

The aqueous oxidation of zinc sulfide in dilute HCl solution at acidic media are studied by means of an electrochemical method. Electrolytes used are dilute HCl solutions contained NaCl with pH values 1∼3 and deaerated with nitrogen gas. The test electrodes are form a mixture of electric conductive paint and metallic sulfide.
Both anodic and cathodic polarization behaviors are measured by means of a potentiodynamic polarization method.
The experimental results obtained are as follows.
(1) The S⁰ producing type reaction of ZnS dissolution is accelerated in proportion to increasing temperature, at low pH values and within a suitable range of potential. The overall reaction is as follows.
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The half-cell reaction are:
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and
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(2) The S⁰ producing type reaction of ZnS dissolution is accelerated by the activation treatment of ZnS. Its reaction increases proportionally with increasing concentration of CuS in place of the ZnS surface layers. The S⁰ produced by the anodic oxidation of ZnS is amorphous sulupher.
(3) The acceleration of the S⁰ producing type reaction in the dissolution of activating ZnS is caused by the formation of a galvanic cuople of the ZnS-CuS system. In this case, ZnS is anodic and CuS exists as the cathode to the reduction of aqueous oxygen in the solution.